If this was 15+ years ago they'd be quiet and never say a word, like any older WMAF couple. They'd be happy being accepted into white spaces and having half white children.
However now you can gain social, and sometimes real, capital by being an ally or activist, so they go out our their way to do that... and yeah there's probably some "guilt" e.g. "I only experience my culture through food I bring my white bf to so I need to make up for that via activism".
Thing is it shouldn't matter what your partner is, everyone should be outraged at these news. But yelling on Twitter about white people all day and then going home to a white man who provides you the economical comfort and social acceptance you desire makes you hypocritical.